Elucidating how synapses are formed and maintained is critical to understanding both the developmental wiring of brain circuits and the long term changes that occur during learning and memory. Furthermore, there is a strong link between synaptic misregulation and brain diseases; for example, Alzheimer's disease neurodegeneration is preceded by synaptic dysfunction and loss. The Garner laboratory has made great strides in understanding synaptogenesis with the discovery of specialized vesicles, termed PTVs, critical for delivering proteins to newly formed synaptic active zones (AZs). We hypothesize that a subset of the proteins on PTVs are necessary for forming functional AZs. Mass spectrometry and proteomic approaches will be used to identify specific protein constituents of PTVs and determine the likely candidates for tethering AZ-specific proteins to this vesicle. siRNA knockdown of PTV proteins in combination with imaging of synapse markers and FM4-64 recycling will be used to determine which of these novel proteins are responsible for generating PTVs and for forming a structural and functional synapse. These studies will provide critical information about the proteins which regulate synaptogenesis [unreadable] [unreadable]